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Abstract:

A synthetic fuel formula using a blend of High Density Synthetic (HDS)
(e.g. Decalin and Tetralin), and Low Density Synthetic (LDS) (e.g.
Synthetic Paraffinic Kerosene--SPK) is disclosed. This HDS and LDS blend
has been shown to be useful as a jet, rocket and diesel fuel of standard
density, and under low temperature conditions. The inventions described
herein relate to 100% synthetic hydrocarbon fuels derived from various
carbonaceous materials such as, but not limited to, biomass, municipal
waste, natural gas, and coal. This 100% synthetic fuel can be universally
used for both jet and diesel fuels. It meets Joint Battlefield Use Fuel
of the Future (J-BUFF), or Single Battlefield Fuel (SBF) strategic
requirements. The commercial advantage of the present invention is that
it can be prepared from commercial available fuel stocks or co-processed
using currently available chemical processes.

14. The formula of claim 1, which results in said joint fuel with
existent gum, particulate, filtration time, water reaction and separation
rating that complies with jet and rocket fuel specifications.

15. The formula of claim 1, wherein said joint fuel conductivity and
lubricity does not rely on sulfur compounds to meet jet and diesel fuel
specifications

16. The formula of claim 1, wherein said joint fuel is compatible with
jet and diesel engine fuel systems. Said joint fuel is interchangeable
with petroleum fuel.

17. The formula of claim 1, wherein said joint fuel is cleaner burning
and lower in sulfur than conventional petroleum jet or diesel fuel.

18. The formula of claim 1, said joint fuel meets known military and
commercial jet and diesel fuel specifications. The fuel formula of claim
1, wherein said HDS derived from Low Temperature Carbonization (LTC), and
said LDS obtained by gasification coupled with Fischer-Tropsch synthesis
are synergistically blended.

20. The fuel formula of claim 1, wherein said HDS derived from Low
Temperature Carbonization (LTC), and said LDS obtained by gasification
coupled with Fischer-Tropsch synthesis are synergistically co-produced.

Description:

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to the field of a joint synthetic
fuel formula for jet, rocket, or diesel engines, which contains a blend
of high density synthetic (HDS) and low density synthetic (LDS) fuels.

[0003] 2. Description of Related Art

[0004] Modern civilization is heavily dependent on crude oil for producing
chemical feedstocks and petroleum fuels typically used in combustion
engines. Due to the recent increase in demand for fuel from around the
world, and the limited production of crude oil, there has been an
increase in the price of liquid transportation fuels. In order to
increase production of liquid fuel, low cost alternative fuels are needed
to meet the ever increasing demand.

[0005] There is a vast amount of prior art available regarding non-fossil
fuel denoted as carbonaceous feedstocks that can be used for the
production of synthetic transportation fuel. Some of the more common
carbonaceous feedstocks are coal, biomass, and solid municipal wastes.

[0006] The Coal, biomass and carbonaceous waste can be converted to a
gaseous or liquid fuel by processes commonly referred to as pyrolysis and
also by gasification and subsequent reforming by catalytic molecular
synthesis.

[0007] Pyrolysis, or more specifically Low Temperature Carbonization
(LTC), results in the chemical decomposition of organic materials such as
biomass, solid waste or coal. LTC is accomplished by heating in the
absence of oxygen. The Karrick process is an example of the pyrolysis of
coal, but this process also results in retaining the desired cycloalkane
ring structure necessary for HDS. Fuels produced by LTC typically have a
density higher than normal for jet and diesel fuel.

[0008] In gasification, organic molecules from solid feedstocks are
chemically degraded into smaller molecular weight molecules, known as
producer gases, synthetic gas or syngas. Syngas is a mixture mainly
consisting of carbon monoxide (CO) and hydrogen (H2) that may be
used as a fuel formulation feedstock. Syngas can be processed into liquid
fuels (such as, gasoline, diesel, jet fuel, etc.) by the Fischer-Tropsch
(FT) synthesis process. Fuel produced by this method is known as
Synthetic Paraffinic Kerosene (SPK) fuel. Fuels made from this process
have a density lower than petroleum jet and diesel fuel. Thus, SPK is
classified as LDS fuel for the purpose of the invention described herein.

[0009] A significant effort is under way to certify FT synthetic fuels,
SPK, for use in U.S. and international aviation fleets. However, because
the majorities of SPK are linear alkanes which do not contain highly
branched alkanes or aromatic compounds containing high energy content per
molecule. SPK lack certain properties suitable for jet and diesel fuels,
e.g. seal swelling property for o-ring of engines. The thermal stability
of SPK derived fuel is also lower than petroleum derived fuel which may
contain aromatic compounds or highly branched alkanes. Consequently, SPK
derived fuel is required to be blended with petroleum-derived fuel or
other additives for the use of jet and diesel engines.

[0010] More specifically, by way of example, U.S. PreGrant Publication No.
2010/0108568 mentioned that straight run FT products have some inherent
drawbacks in meeting Jet A-1 and/or Battlefield Use Fuel of the Future
(BUFF) specifications, namely a high content of linear alkanes that
result in a high freezing point and low temperature viscosity and a low
aromatic content. The invention disclosed in U.S. PreGrant Publication
No. 2010/0108568 provides a FT jet fuel refining process which includes a
step to aromatize one or more of an FT syncrude fraction. The objective
is to provide a SPK that meets Jet A-1/JP-8 and/or JP-5/BUFF
specifications. The present invention is distinguished from this prior
art because the invention utilizes commercially available fuel stocks
obtained from the technically and commercially established chemical
syntheses/processes.

[0011] ASTM International published a new fuel specification for aviation
turbine fuels containing synthesized hydrocarbons, D7566, which is made
of renewable feedstocks such as algae, jatropha-based, camelina-based
SPK. This resulting fuel is virtually identical to jet fuel except it
doesn't contain aromatic compound. The aromatic compound add density to
the fuel and help maintain proper seal swell. Because of this lack of
aromatics in bio-SPK, it is blended with 50% blend of petroleum-derived
fuel that provides enough aromatics for adequate o-ring seal swell. The
present invention is distinguished from this prior art in that a blend of
two synthetic fuels derived from biomass, coal and carbonaceous waste are
used instead of petroleum.

[0012] U.S. Pat. Nos. 7,683,224 and 7,560,603 disclose a method to make
jet and diesel fuel that doesn't need to blend with petroleum-derived
fuel to provide aromatics for adequate seal swell. Its method alkylates
linear and lightly branched alkanes with aromatic moieties to make
monoaromatics for use in jet and diesel fuels. A fuel has such
monoaromatics having multiple desired properties such as higher flash
point, low pour point, increased density, better lubricity, aerobic
degradability, and additionally can deliver benefits in blendstocks. The
present invention does not need extra synthesis in order to gain
properties meeting jet and diesel fuel specification.

[0013] U.S. PreGrant Publication No. 2009/0013591 disclose an alternative
gasoline, diesel fuel, marine diesel fuel, jet fuel, and flexible fuel
compositions. The compositions include an alcohol and/or a glycerol ether
or mixture of glycerol ethers, which can be derived from renewable
resources.

[0014] In U.S. PreGrant Publication No. 20100011778A, a process of energy
production is disclosed. The process includes integrating three or more
energy production technologies such that a first byproduct of a first
energy production technology is applied to a second energy production
technology and a second byproduct of the second energy production
technology is applied to a third energy production technology. The
related art disclosed a process that integrates three or more energy
production technologies in a series arrangement. Nevertheless, the
invention disclosed here is a fuel composition that can be prepared by
mixing and stirring of two products (HDS fuel and LDS fuel) from Karrick
process and FT synthesis although the byproduct (CO or H2) from
Karrick process can be applied to FT synthesis. The two products (HDS
fuel and LDS fuel) can also be co-produced in parallel. In addition, the
prior art does not claim composition of matter.

[0015] Although the aforementioned related art provide examples of a fuel
or fuel blendstock for jet, rocket, and diesel engines, they involve more
complex synthesis or processes in order to produce the desired joint
fuels. The present invention is directed at an improved fuel formula that
results in a 100% joint synthetic diesel and jet fuel (JSF) using a blend
of HDS and LDS fuels, which are commercially available or can be produced
by well known processes currently available. JSF overcomes the
shortcomings which were discussed above and/or other shortcomings in
existing technology.

SUMMARY OF THE INVENTION

[0016] Specification for certain jet, rocket and diesel application
requires that the fuel utilized have a high density and be easily
ignitable and capable of sustaining combustion at temperature of -47 C,
and possibly lower. In applications such as jet engines and high altitude
rocket engines, specifications also call for fuels having highly
reproducible properties. Suitable fuels must also be stable at high
temperatures and not deteriorate under a wide variety of shelf-life
conditions.

[0017] In numerous DoD presentations the concept of Joint Battlespace Use
Fuel of the Future (JBUFF) or a Single Battlespace Fuel (SBF) has been
presented to use one fuel for all military applications on land, sea and
air. A JBUFF fuel will allow for rapid deployment and logistic
enhancement for military and emergency aid environments where various
types of equipment can be operated with one fuel in place of several
types of fuel. The present invention is directed to the formula for
producing JSF to meet the chemical system needed for this concept. The
present invention also provides a composition of matter for both
commercial and military jet and diesel fuels.

[0018] In an exemplary embodiment of the present invention, there is
disclosed an improved fuel formula that results in a 100% JSF for jet,
rocket and diesel engines using biomass, municipal waste, natural gas or
coal feedstocks. The fuel formula comprises HDS fuel, LDS fuel and/or
minor additives. The HDS fuel is essentially Decalin and Tetralin. The
LDS fuel is SPK. The preferred fuel formulation of this invention is a
mixture of at least 40% by weight decalin/tetralin and remainder
synthetic paraffin.

[0019] As such, those skilled in the art will understand that the
conception, upon which this invention is based, may readily be utilized
as a basis for the designing of other formula for carrying out the
several purposes of the present invention. It is important, therefore,
that the claims be regarded as including such equivalent constructions
insofar as they do not depart from the spirit and scope of the present
invention.

[0020] The foregoing has outlined, rather broadly, the preferred feature
of the present invention so that those skilled in the art may better
understand the detailed description of the invention that follows.
Additional features of the invention will be described hereinafter that
form the subject of the claims of the invention. Those skilled in the art
should appreciate that they can readily use the disclosed conception and
specific embodiment as a basis for designing or modifying other
structures for carrying out the same purposes of the present invention
and that such other structures do not depart from the spirit and scope of
the invention in its broadest form.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Other aspects, features, and advantages of the present invention
will become more fully apparent from the following detailed description,
the appended claim, and the accompanying drawings in which similar
elements are given similar reference numerals.

[0022] The accompanying drawing, which are incorporated in and constitute
a part of this specification, illustrate the embodiment of the invention
and together with the description, serve to explain the principles of the
invention.

[0023] FIG. 1 is a schematic of the formulation of JSF through blending or
co-processing according to one embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0024] Referring to FIG. 1, there is disclosed a schematic of the
formulation of JSF through blending or co-producing according to one of
embodiment of the invention.

[0025] The HDS can be obtained through pyrolysis. The Karrick process is
an example of the pyrolysis of coal which leads to retaining of the
desired cycloalkane ring and/or hydroaromatic ring structure, which are
necessary for certain physical properties, e.g. high density, higher
stability in comparison with SPK and good seal swelling property.
Particularly, the cycloalkane and hydroaromatic compounds have higher
thermal stability relative to the stability of n-alkanes that are major
components of the SPK, and thus can attribute to the thermal stability of
the jet and diesel fuels. The seal swelling properties is also critical
to the gasket o-ring sealing to prevent the jet fuel tank from leaking.
The HDS fuel of this invention is essentially Decal in
(decahydronapthalene) and Tetral in (tetrahydronapthalene) of which the
density is higher than normal for jet and diesel fuel.

[0026] The LDS can be derived by gasification and/or reformation coupled
with FT synthesis. The LDS fuel produced by this method is known as SPK
and has a density lower than petroleum jet and diesel fuel. The
shortcomings of SPK, for example, low density, low thermal stability, and
poor seal swelling property can be overcome by HDS fuel mentioned above.

[0027] Decalin and Tetralin (both naphthalene derivatives) are completely
miscible with paraffin. These two naphthalene derivates are also
completely miscible with each other. Therefore, the fuel formulations of
this invention may be prepared by mixing and stirring the commercially
available ingredients. When the HDS fuel (essentially Decalin and
Tetralin) and LDS fuel (SPK) are synergistically blended or co-processed,
the resulting formula of the invention has the density consistent with
conventional petroleum jet and diesel fuel. This formula meets
specification for jet, rocket, and diesel fuels in that the formula
exhibits highly reproducible properties, has correct density, and has
freeze points and flash points which permit ignition and sustained
combustion at -47 C. A mixture of at least 40% by weight Decalin/Tetralin
and remainder synthetic paraffin freezes at below -57 C. This is the
preferred fuel formulation of this invention.

[0028] The further addition of minor additives assures conformity of other
fuel properties such as lubricity and conductivity. The density of fuel
produced with this formula is consistent with conventional petroleum jet
and diesel fuel. This results in the embodiment described herein to be
classified as a "drop-in" alternative to either jet or diesel fuel. The
superior thermal stability and long shelf life properties of JSF makes it
an ideal rocket fuel.

[0029] The embodiment disclosed in FIG. 1 comprises (a) a HDS fuel from
about 40% to about 55% by weight of the fuel formula; (b) a LDS fuel from
about 45% to about 60% by weight of the fuel formula; and (c) additives
from about 0% to about 5% by weight of the fuel formula.

[0030] It will be apparent to those skilled in the art that various
modifications and variations can be made to the disclosed formula for
joint synthetic jet and diesel fuel without departing from the scope of
the invention. Other embodiments of the invention will be apparent to
those skilled in the art from consideration of the specification and
practice of the invention disclosed herein. It is intended that the
specification and examples be considered as exemplary only, with a true
scope being indicated by the following claims and their equivalents.

[0031] While there have been shown and described and pointed out the
fundamental novel features of the invention as applied to the preferred
embodiments, it will be understood that the foregoing is considered as
illustrative only of the principles of the invention and not intended to
be exhaustive or to limit the invention to the precise forms disclosed.
Obvious modifications or variations are possible in light of the above
teachings. The embodiments discussed were chosen and described to provide
the best illustration of the principles of the invention and its
practical application to enable one of ordinary skill in the art to
utilize the invention in various embodiments and with various
modifications as are suited to the particular use contemplated All such
modifications and variations are within the scope of the invention as
determined by the appended claims when interpreted in accordance with the
breadth to which they are entitled.